Editing Codex Astartes (section)

==What the Codex set out to Accomplish==

{{Topquote|The Code is more what you'd call ''guidelines'' than actual rules.|Captain Barbosa illustrating how Guilliman intended his Codex to actually function}}

The Codex Astartes was written with three main purposes in mind.

First, the Codex is a tactical and strategic guide, containing tips and plans on how to handle nearly any battle situation imaginable and then some. The Codex served with flying colors until the modern day of the setting when its weaknesses began to show against certain [[Tyranids|unconventional]] [[Necrons|enemies]]. Much like ''The Art of War'' or the FBI tactical guidebook, if you can get your hands on a copy you can anticipate the actions of those that use it, but countering it is '''really''' fucking hard because of just how comprehensive the Codex is. It doesn't just tell you "When your enemy is doing B, do C to counter it," it also says, "And when the enemy counters C with X and Y, use Z to shut down their counter." In real life warfare, soldiers have a hard time adapting to new information under pressure, which is why commanders need to limit the orders they give to their troops and keep them as unambiguous and simple as possible; drilling them on exactly what to do in a given situation, especially in such a comprehensive manner, does have its advantages since it reduces mental clutter. Sun Tzu's ''Art of War'' is still being taught millennia after its publication; now imagine that same spark of tactical genius manifesting inside the mind of a superhumanly intelligent demigod. The Codex isn't perfect - no tactical treatise is - but it's damn close.

Second, the Codex is an organizational guide. Guilliman was a flawed genius, an organizational savant literally unmatched in the galaxy and more than a little OCD when it came to detail. Beyond simple mandates about the composition of the Chapters, the Codex contains information on the minutia of administration, with details on every subject from bolt shells to bread, water distribution to weapon production, organization of auxiliary forces, suggested countermeasures to [[Nurgle|viral]] outbreaks, training schedules, troop morale, ammunition production, distribution of that ammunition to terrestrial and naval combat units, how large reserves can be built up, how long those reserves will last when production stopped, ration distribution for militant and civilian populations, how those rations can be stored, food cycling to avoid waste, integration of chain of command with allied and auxiliary forces, integration of militia into formal military, suggested staging area locations relative to battle lines, suggested landing area locations relative to battle lines, prioritizing access to and from these areas, [[derp|guides to avoiding massive compound sentences]], fortification locations, demolition strategies for those fortifications in the event that they must be abandoned, and more. It also has plenty to say on how to live your day-to-day life with everything from codes of honor to follow, to how your boots should be laced. Seriously, the Codex can tell you how to spend every minute of your life from birth to death, and pretty much every part of it is either acceptable or outstanding if admittedly inflexible. Much of it, if applied to the Imperium as a whole, would also solve most of the grimdark.

Finally, and perhaps most importantly, the final version of the Codex is designed to keep the power of the Imperium decentralized. At the end of the Heresy, Guilliman wanted to ensure there wouldn't be any repeating performances of the strife that had gripped the galaxy. To this end, he tried to unite all Astartes into a single Legion but the High Lords went ape shit about this so instead he split the Imperial Army into the [[Imperial Navy]] and the [[Imperial Guard]] and broke up the Legions, to keep one person from ever having the power to cause such massive chaos. Whether or not this was a good move is [[skub|a subject of ongoing debate]]. Detractors would point out that the newly decentralized and feudal Imperium (decentralized in lack of leadership organization, not in the layers of governing sense) is nowhere near as capable of unified action as it was before the heresy, pointing at how this decentralization screwed the Imperium over during [[the War of The Beast]], while its defenders would point out the examples of The [[Badab War]] or the [[Macharian Crusade]] as examples of too much centralized power devolving into a clusterfuck even though the Badab War was an issue because the Badab side had strong organization while the Imperials did not and the Macharian Heresy was because of a lack of leadership and organization and therefore both are just more examples of why poor organization and coordination is bad, to say nothing of the Horus Heresy demonstrating why giving any one person too much power over the Imperium is a ''very bad idea'' but then again even if he had no authority the people who chose to follow him would have made that choice regardless, they aren’t mindless wind-up toys. But, really, the problem in all examples of too much power under one person was A) that person not being carefully watched by someone else and B) everyone under them being indoctrinated for mindless obedience to orders. Considering the Imperium has solved A but still heavily emphasizes B, it really could go either way. A large scale rebellion isn't really something the Imperium needs to fear regardless of who has how much power as people will rally to anyone they believe in, but someone with power over a lot of forces could easily deploy them in ways that strategically weakens the Imperium. It's not uncommon for corrupted/traitorous commanders to send regiments into traps, for example.

However, one thing that people often forget when they argue about whether Legions or post-Heresy Chapters are better is that the Legions and Chapters have very different roles. Legions of a hundred thousand Astartes are great when you want to steamroll the galaxy - which is exactly what the original Legions designed for - but not so great when you want to maintain peace in a sprawling galaxy-spanning empire. What the post-[[great Scouring|Scouring]] Imperium really needed were small-scale elite rapid-response forces, which is exactly the kind of role that the Chapters are most suited for. Well, that coupled with a large normal army to act as first-responders very quickly and hold the line for the big boys to come smash face. Come to think of it, this is very much like how real life destroyers worked in WW2, how infantry work in a mechanized infantry unit, and other such things. Fitting, since Space Marines are basically living tanks.

This is also a much more efficient use of the Astartes. You don't need a space marine to man a gun line or garrison a fort - why let a marine do a guardsman's job? - and considering how long it takes to create a fully-fledged Astartes, you'll want to get the most out of every single one of them. Remember also that there weren't all that many loyalist Astartes left alive after the Heresy. Getting a thousand Astartes killed just to win a battle may have been A-OK during the Great Crusade or the Heresy, but the post-Heresy Imperium just couldn't afford losses like that anymore (for a while, at least), so it only makes sense for the space marines to conform to tactics where your average space marine battle will result in few marine casualties. Guilliman designed the Codex marine armies to be modular, precise, and efficient in ways that the original legions weren't.

Of course, the tradeoff is that the marines are no longer well suited for large-scale warfare. But large-scale warfare and armoured warfare are now the Imperial Guard's job, anyway. On top of that Legion-sized (or at least multichapter) deployments can and will still happen whenever necessary, like with the [[Armageddon|Armageddon wars]], the [[Black Crusade|Black Crusades]] or the Wall of the Imperial Fist Legion during the War of the Beast. That said, there are situations in M41 where the Legions of old would probably be more effective than any gathering of Chapters: the [[Tyranids]] and the bigger [[Necrons|Necron]] dynasties come to mind, though there's also less formidable threats like the [[Tau]]. But even there the Guard is a perfectly fine substitute for a Legion in most if not all of those cases, especially with their godly mechanization, tanks, and artillery. Hell, their standard procedure is to simply use various artillery to eradicate everyone and everywhere the enemy could hide (bunkers, trenches, buildings, tunnels, ''anything'') then send in tanks to wipe out any resistance and the ground pounders to hunt down the survivors. We have billions of Guardsmen dying every day, but the number of Guardsmen in total makes losing billions a day look like a figurative drop in a figurative ocean. This means that the Astartes are not needed nearly as often as the Guard, especially since the Guard almost always operates on the defensive, which means that line-breaking supersoldier armies are rarely needed.

Interestingly enough, the original version of the Codex had no plans to break apart the Legions at all. Instead, it proposed their unification into a single Legion formed from multiple self-sufficient Chapters, which would merge and break up as needed regardless of which Primarch they descended from. While this may have been able to preserve the advantages of being a Legion better, the other [[High Lords of Terra]] were scared shitless by the idea of the Space Marines unifying and promptly rebelling a second time, so the original plan never came to pass. Even the idea of it happening was enough for the 41st millennium-era High Lords to plot Guilliman's overthrow when they heard he might resume his old position, which shows how little they know. The Primarchs are the sons of the Emperor for a reason. They are '''''really fucking scary dudes'''''. Besides, the Space Marines would unify as much or as little as they choose and there really isn't anything the High Lords can do about it so their concerns over Guilliman's original intentions for Chapters didn't matter and the changes didn't either. They still operate the same way Guilliman had intended but with far less communication and co-ordination unless they needed. Since they usually aren't needed, it doesn't really matter at all.

When Guilliman was finally revived, he began to see the flaws that came from strict adherence to the Codex Astartes which were partially his fault from paranoia after the Heresy, and others that had arisen as he wasn't around to correct them given he spent nearly ten thousand years in stasis moments from death. Thus, he has begun reforming its guidelines and got rid of several of its restrictions on Space Marines. He currently hopes to replace it entirely with the Codex Imperialis - a tome that won't just describe how to organize and direct the Adeptus Astartes or even the other [[Imperial Guard|Imperial]] [[Imperial Navy|military]] [[Planetary Defense Force|forces]], but Imperial governance as a whole possibly down to the ideal daily lives of every Imperial citizen, likely in an attempt to make the entire Imperium [[NobleBright|look and operate as smoothly as Ultramar]]. Needless to say, this will probably be the size of a 10 volume encyclopedia, and still hasn’t been finished.